Manufacture of lamp stems



1950 w. J. KNOCHEL ET AL 2,535,582

MANUFACTURE OF LAMP STEMS Filed 0st. 15. 1946 Patented Dec. 26, 1950 UNITED STATES ATENT OFFICE MANUFACTURE OF LAMP STEMS,

Application October 15, 1946, Serial No. 703,418

1 Claim.

This invention relates to the manufacture of stems, and particularly such for electric lamps.

The principal object of our invention, generally considered, is to facilitate the manufacture of stems, each of which involves a flare tube and an exhaust tube or tubulation uniting at a press through which pass leads on either side of an embedded support hook, said leads being continued inwardly beyond the press and sufficiently stifi to support the ends of a filament, an intermediate portion of which is supported by the hook.

Another object of our invention is to avoid shrinkage in the manufacture of lamps, particularly such of the type described and claimed in the Morehead Patent No. 2,392,333, dated January 8, 1946, wh le avoiding misplacement of the center support hook during assembly by reason of said hook not being centered properly during stem making.

A further object of our invention is to facilitate the manufacture of lamp stems, and particularly those having a center hook through which the filament passes, comprising fusing such a hook into an end of the exhaust tube or tubulation, placing said hook in the center pocket of a jig, with the connected exhaust tube projecting upwardly, placing lead-in conductors in jig pockets on either side of said hook pocket, disposing a flare tube over said exhaust tube and leads, applying heat and pressure to cause said flare tube to fuse about said leads and to said exhaust tube, and developing fluid pressure in said exhaust tube too blow an outlet therefrom through the press uniting said parts.

A still further obiect of our invention is to manufacture lamp stems by first sealing a tubulation or exhaust tube to a nickel center support hook on a heading machine, and feeding the tube-hook assembly to the weld pocket, whereby elimination of the necessity to separately place the hook and tubulation in the stem-making machine by pre-consolidation of the hook and exhaust tube, gives the operator more time to properly feed said machine, thereby avoiding a large amount of shrinkage.

Other objects and advantages of the invention will become apparent as the description proceeds.

Referring to the scale drawing-- Figure 1 is an elevational view of a based lamp embodying a stem manufactured in accordance with our invention.

Figure 2 is an elevational view of a stem for such a lamp.

Figure 3 is an elevational view, with parts in axial section, showing the first manufacturing step in which the tubulation or exhaust tube is fitted over and fused to a metal member adapted to function as the center support hook of the stem.

Figure 4 is a sectional view of the tubulation in the end of which a nickel hook has been fusedly embedded.

Figure 5 is an elevational view, with parts in vertical section, showing a jig, or head of a mounting machine, in a center pocket of which isdisposed the hook on the end of the exhaust tube, and in pockets on either side thereof are positioned leads, an associated flare tube being disposed on top of said jig and encircling the assembled parts.

Figure 6 is a view of the mounting machine carrying the head or jig holding the assembled parts, fires being shown in the process of consolidating said parts prior to molding a press by associated jaws.

Figure '7 is a similar view, showing the stem after consolidat on of the parts and formation of the press, with a pipe for blowing air down the exhaust tube to form an outlet from it to the press adjacent the connection with the flare-tube.

Prior to the use of our invention, considerable shrinkage occurred when manufacturing stems, each comprising a flare tube consolidated with an exhaust tube or tubulation, and through the uniting press of which passed leads, preferably formed of nickel or other relatively stiif material, to support the ends of an associated filament, a preferably nickel hook being disposed between said leads and holding an intermediate portion of said filament when the mount was completed. One of the major causes of shrinkage was the dis lacement of the nickel center support hook with respect to the press to be formed. This was caused by the hook not being centered properly during stem making. During the operation of feeding the parts to the weld packet the tubulation should be made to fit over the center support hook, for then and only then can the book be sealed while properly centered.

Since it is almost impossible for an. operator to feed .020" Kovar lead wires, a center support hook of nickel or the like, and a glass flare, and place the tubulation over the center support hock during the normal indexing time of a stem-making machine, it became necessary to find a way to hold the center support hook so that the operator would have enough time to fe d the machine,

In accordance with our invention, we seal the intermediate or center metal support element or hook ll, of nickel or the like, to one end of the exhaust tube or tubulation l 2, as by placing said hook in a jig or the head l3 on a heading ma chine I4, placing the exhaust tube so that it fits over said hook, as illustrated in Figure 3, and is supported by suitable means, such as an apertured bracket l5 on said machine, and applying heat as by means by gas fires It to fusethe end portion of said exhaust tube around one end of said hook II, as indicated at I7 in Figure 4.

The assembled exhaust tube and hook are then transferred to a jig or the head 18 of a mounting machine, said head having an upwardly opening center pocket l9 receiving the hook H, and pockets 2| and 22 on either side thereof for receiving lead-in conductors 23 and 24, of Kovar or other suitable metal. After placing the conductors on opposite sides of the assembled exhaust tube and hook, a flare tube 25 is disposed about the associated parts, as illustrated in Figure 5.

With an assembled exhaust tube 12 and hook I I held in place, as by suitable means 25 such as an apertured bracket or a pair of jaws, fires 27 are directed at the lower portion of the flare tube 25 and jaws 28, 29 are actuated, in known manner,

to consolidate and press said tube about leads 23 and 24 and exhaust tube I! from which projects the hook I l as shown in Figure 6.

While the glass at the junction between the press and associated parts is, still soft. a blast of fluid pressure, such as air from pipe 32, blows an opening 33 through the glass junction, as illustrated in Figure 7. The exhaust tube thus has access to an associated bulb 34, to which the stem formed into a mount by bending the inner ends of the leads, as indicated at 35 and 35 in Figure 1, connectin a filament 37 thereto, the intermediate portion of said filament being supported by said hook I I, is connected.

From the foregoing, it will be seen that we facilitate the manufacture of stems and mounts by pro-consolidating the exhaust tube or tubulation and supporting hook, thereby not only avoiding the possibility of the hook getting displaced during manufacture, but eliminating the necessity of the operator handling such a small part during mounting, thereby also allowing suflicient time for proper feeding of the machine.

The Lempert et al. Patent No. 2,279,831, dated April 14, 1942, is referred to for the formula of Kovar.

By virtue of our invention a great deal of shrinkage has been eliminated. Although it has been shown particularly adapted for a certain type of lamp, it will. be understood that the invention is limited only by the spirit and scope of the appended claim.

We claim:

The method of machine-making stems, each of which comprises a flare tube, an exhaust tube, leads, and a small metal support member to lie between the inner portions of said leads, compris ing fusing one end of said metal support member WILLIAM J. KNOCHEL. CHARLES WIEN'ER REFERENCES CITED The following references are of record in the .flle of this patent:

UNITED STATES PATENTS Name Date Phelps et a1 Feb. 21, 1928 Kintner July 7, 1931 FOREIGN PATENTS Country Date France Jan. 7, 1928 Number Number 

